Adds retry mechanism for whitesource in case the download of the unified agent or JRE fails (#2961)

pkg/whitesource/scanUA.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"strings"
 	"sync"
 
 	"github.com/SAP/jenkins-library/pkg/log"
@@ -176,6 +177,17 @@ func downloadAgent(config *ScanOptions, utils Utils) error {
 	}
 	if !exists {
 		err := utils.DownloadFile(config.AgentDownloadURL, agentFile, nil, nil)
+		if err != nil {
+			// we check if the copy error occurs and retry the download
+			// if the copy error did not happen, we rerun the whole download mechanism once
+			if strings.Contains(err.Error(), "unable to copy content from url to file") {
+				// retry the download once again
+				log.Entry().Warnf("Previous Download failed due to %v", err)
+				err = nil // reset error to nil
+				err = utils.DownloadFile(config.AgentDownloadURL, agentFile, nil, nil)
+			}
+		}
+
 		if err != nil {
 			return errors.Wrapf(err, "failed to download unified agent from URL '%s' to file '%s'", config.AgentDownloadURL, agentFile)
 		}
@@ -193,7 +205,18 @@ func downloadJre(config *ScanOptions, utils Utils) (string, error) {
 	javaPath := "java"
 	if err != nil {
 		log.Entry().Infof("No Java installation found, downloading JVM from %v", config.JreDownloadURL)
-		err := utils.DownloadFile(config.JreDownloadURL, jvmTarGz, nil, nil)
+		err = utils.DownloadFile(config.JreDownloadURL, jvmTarGz, nil, nil)
+		if err != nil {
+			// we check if the copy error occurs and retry the download
+			// if the copy error did not happen, we rerun the whole download mechanism once
+			if strings.Contains(err.Error(), "unable to copy content from url to file") {
+				// retry the download once again
+				log.Entry().Warnf("Previous Download failed due to %v", err)
+				err = nil
+				err = utils.DownloadFile(config.JreDownloadURL, jvmTarGz, nil, nil)
+			}
+		}
+
 		if err != nil {
 			return "", errors.Wrapf(err, "failed to download jre from URL '%s'", config.JreDownloadURL)
 		}

pkg/whitesource/scanUA_test.go

@@ -2,12 +2,11 @@ package whitesource
 
 import (
 	"fmt"
+	"github.com/SAP/jenkins-library/pkg/log"
+	"github.com/stretchr/testify/assert"
 	"path/filepath"
 	"strings"
 	"testing"
-
-	"github.com/SAP/jenkins-library/pkg/log"
-	"github.com/stretchr/testify/assert"
 )
 
 func TestExecuteUAScan(t *testing.T) {
@@ -291,6 +290,17 @@ func TestDownloadAgent(t *testing.T) {
 		err := downloadAgent(&config, utilsMock)
 		assert.Contains(t, fmt.Sprint(err), "failed to download unified agent from URL")
 	})
+	t.Run("error - download with retry", func(t *testing.T) {
+		config := ScanOptions{
+			AgentDownloadURL: "errorCopyFile", // Misusing this ScanOptions to tell DownloadFile Mock to raise an error
+			AgentFileName:    "unified-agent.jar",
+		}
+		utilsMock := NewScanUtilsMock()
+		utilsMock.DownloadError = map[string]error{"https://download.ua.org/agent.jar": fmt.Errorf("unable to copy content from url to file")}
+
+		err := downloadAgent(&config, utilsMock)
+		assert.Contains(t, fmt.Sprint(err), "unable to copy content from url to file")
+	})
 }
 
 func TestDownloadJre(t *testing.T) {
@@ -350,6 +360,18 @@ func TestDownloadJre(t *testing.T) {
 		assert.Contains(t, fmt.Sprint(err), "failed to download jre from URL")
 	})
 
+	t.Run("error - download with retry", func(t *testing.T) {
+		config := ScanOptions{
+			JreDownloadURL: "errorCopyFile",
+		}
+		utilsMock := NewScanUtilsMock()
+		utilsMock.ShouldFailOnCommand = map[string]error{"java": fmt.Errorf("failed to run java")}
+		//utilsMock.DownloadError = map[string]error{"https://download.jre.org/jvm.jar": fmt.Errorf("failed to download file")}
+
+		_, err := downloadJre(&config, utilsMock)
+		assert.Contains(t, fmt.Sprint(err), "unable to copy content from url to file")
+	})
+
 	t.Run("error - tar execution", func(t *testing.T) {
 		config := ScanOptions{
 			JreDownloadURL: "https://download.jre.org/jvm.jar",

pkg/whitesource/utilsMock.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/SAP/jenkins-library/pkg/mock"
 	"github.com/SAP/jenkins-library/pkg/piperutils"
+	"github.com/pkg/errors"
 )
 
 func newTestScan(config *ScanOptions) *Scan {
@@ -67,6 +68,9 @@ func (m *ScanUtilsMock) InstallAllNPMDependencies(_ *ScanOptions, packageJSONs [
 
 // DownloadFile mimics http.Downloader and records the downloaded file.
 func (m *ScanUtilsMock) DownloadFile(url, filename string, _ http.Header, _ []*http.Cookie) error {
+	if url == "errorCopyFile" {
+		return errors.New("unable to copy content from url to file")
+	}
 	if m.DownloadError[url] != nil {
 		return m.DownloadError[url]
 	}